/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.net;

import java.io.IOException;
import java.util.jar.JarFile;
import java.util.jar.JarEntry;
import java.util.jar.Attributes;
import java.util.jar.Manifest;
import java.security.Permission;
import sun.net.www.ParseUtil;

/**
 * A URL Connection to a Java ARchive (JAR) file or an entry in a JAR
 * file.
 *
 * <p>The syntax of a JAR URL is:
 *
 * <pre>
 * jar:&lt;url&gt;!/{entry}
 * </pre>
 *
 * <p>for example:
 *
 * <p>{@code jar:http://www.foo.com/bar/baz.jar!/COM/foo/Quux.class}
 *
 * <p>Jar URLs should be used to refer to a JAR file or entries in
 * a JAR file. The example above is a JAR URL which refers to a JAR
 * entry. If the entry name is omitted, the URL refers to the whole
 * JAR file:
 *
 * {@code jar:http://www.foo.com/bar/baz.jar!/}
 *
 * <p>Users should cast the generic URLConnection to a
 * JarURLConnection when they know that the URL they created is a JAR
 * URL, and they need JAR-specific functionality. For example:
 *
 * <pre>
 * URL url = new URL("jar:file:/home/duke/duke.jar!/");
 * JarURLConnection jarConnection = (JarURLConnection)url.openConnection();
 * Manifest manifest = jarConnection.getManifest();
 * </pre>
 *
 * <p>JarURLConnection instances can only be used to read from JAR files.
 * It is not possible to get a {@link java.io.OutputStream} to modify or write
 * to the underlying JAR file using this class.
 * <p>Examples:
 *
 * <dl>
 *
 * <dt>A Jar entry
 * <dd>{@code jar:http://www.foo.com/bar/baz.jar!/COM/foo/Quux.class}
 *
 * <dt>A Jar file
 * <dd>{@code jar:http://www.foo.com/bar/baz.jar!/}
 *
 * <dt>A Jar directory
 * <dd>{@code jar:http://www.foo.com/bar/baz.jar!/COM/foo/}
 *
 * </dl>
 *
 * <p>{@code !/} is referred to as the <em>separator</em>.
 *
 * <p>When constructing a JAR url via {@code new URL(context, spec)},
 * the following rules apply:
 *
 * <ul>
 *
 * <li>if there is no context URL and the specification passed to the
 * URL constructor doesn't contain a separator, the URL is considered
 * to refer to a JarFile.
 *
 * <li>if there is a context URL, the context URL is assumed to refer
 * to a JAR file or a Jar directory.
 *
 * <li>if the specification begins with a '/', the Jar directory is
 * ignored, and the spec is considered to be at the root of the Jar
 * file.
 *
 * <p>Examples:
 *
 * <dl>
 *
 * <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/</b>,
 * spec:<b>baz/entry.txt</b>
 *
 * <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/baz/entry.txt</b>
 *
 * <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/baz</b>,
 * spec:<b>entry.txt</b>
 *
 * <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/baz/entry.txt</b>
 *
 * <dt>context: <b>jar:http://www.foo.com/bar/jar.jar!/baz</b>,
 * spec:<b>/entry.txt</b>
 *
 * <dd>url:<b>jar:http://www.foo.com/bar/jar.jar!/entry.txt</b>
 *
 * </dl>
 *
 * </ul>
 *
 * @author Benjamin Renaud
 * @see java.net.URL
 * @see java.net.URLConnection
 * @see java.util.jar.JarFile
 * @see java.util.jar.JarInputStream
 * @see java.util.jar.Manifest
 * @see java.util.zip.ZipEntry
 * @since 1.2
 */
public abstract class JarURLConnection extends URLConnection {

  private URL jarFileURL;
  private String entryName;

  /**
   * The connection to the JAR file URL, if the connection has been
   * initiated. This should be set by connect.
   */
  protected URLConnection jarFileURLConnection;

  /**
   * Creates the new JarURLConnection to the specified URL.
   *
   * @param url the URL
   * @throws MalformedURLException if no legal protocol could be found in a specification string or
   * the string could not be parsed.
   */

  protected JarURLConnection(URL url) throws MalformedURLException {
    super(url);
    parseSpecs(url);
  }

  /* get the specs for a given url out of the cache, and compute and
   * cache them if they're not there.
   */
  private void parseSpecs(URL url) throws MalformedURLException {
    String spec = url.getFile();

    int separator = spec.indexOf("!/");
        /*
         * REMIND: we don't handle nested JAR URLs
         */
    if (separator == -1) {
      throw new MalformedURLException("no !/ found in url spec:" + spec);
    }

    jarFileURL = new URL(spec.substring(0, separator++));
    entryName = null;

        /* if ! is the last letter of the innerURL, entryName is null */
    if (++separator != spec.length()) {
      entryName = spec.substring(separator, spec.length());
      entryName = ParseUtil.decode(entryName);
    }
  }

  /**
   * Returns the URL for the Jar file for this connection.
   *
   * @return the URL for the Jar file for this connection.
   */
  public URL getJarFileURL() {
    return jarFileURL;
  }

  /**
   * Return the entry name for this connection. This method
   * returns null if the JAR file URL corresponding to this
   * connection points to a JAR file and not a JAR file entry.
   *
   * @return the entry name for this connection, if any.
   */
  public String getEntryName() {
    return entryName;
  }

  /**
   * Return the JAR file for this connection.
   *
   * @return the JAR file for this connection. If the connection is a connection to an entry of a
   * JAR file, the JAR file object is returned
   * @throws IOException if an IOException occurs while trying to connect to the JAR file for this
   * connection.
   * @see #connect
   */
  public abstract JarFile getJarFile() throws IOException;

  /**
   * Returns the Manifest for this connection, or null if none.
   *
   * @return the manifest object corresponding to the JAR file object for this connection.
   * @throws IOException if getting the JAR file for this connection causes an IOException to be
   * thrown.
   * @see #getJarFile
   */
  public Manifest getManifest() throws IOException {
    return getJarFile().getManifest();
  }

  /**
   * Return the JAR entry object for this connection, if any. This
   * method returns null if the JAR file URL corresponding to this
   * connection points to a JAR file and not a JAR file entry.
   *
   * @return the JAR entry object for this connection, or null if the JAR URL for this connection
   * points to a JAR file.
   * @throws IOException if getting the JAR file for this connection causes an IOException to be
   * thrown.
   * @see #getJarFile
   * @see #getJarEntry
   */
  public JarEntry getJarEntry() throws IOException {
    return getJarFile().getJarEntry(entryName);
  }

  /**
   * Return the Attributes object for this connection if the URL
   * for it points to a JAR file entry, null otherwise.
   *
   * @return the Attributes object for this connection if the URL for it points to a JAR file entry,
   * null otherwise.
   * @throws IOException if getting the JAR entry causes an IOException to be thrown.
   * @see #getJarEntry
   */
  public Attributes getAttributes() throws IOException {
    JarEntry e = getJarEntry();
    return e != null ? e.getAttributes() : null;
  }

  /**
   * Returns the main Attributes for the JAR file for this
   * connection.
   *
   * @return the main Attributes for the JAR file for this connection.
   * @throws IOException if getting the manifest causes an IOException to be thrown.
   * @see #getJarFile
   * @see #getManifest
   */
  public Attributes getMainAttributes() throws IOException {
    Manifest man = getManifest();
    return man != null ? man.getMainAttributes() : null;
  }

  /**
   * Return the Certificate object for this connection if the URL
   * for it points to a JAR file entry, null otherwise. This method
   * can only be called once
   * the connection has been completely verified by reading
   * from the input stream until the end of the stream has been
   * reached. Otherwise, this method will return {@code null}
   *
   * @return the Certificate object for this connection if the URL for it points to a JAR file
   * entry, null otherwise.
   * @throws IOException if getting the JAR entry causes an IOException to be thrown.
   * @see #getJarEntry
   */
  public java.security.cert.Certificate[] getCertificates()
      throws IOException {
    JarEntry e = getJarEntry();
    return e != null ? e.getCertificates() : null;
  }
}
